In the conventional industrial-type incinerator for burning waste material, air is introduced into the lower end of the combustion chamber for primary combustion purposes, and frequently, secondary air is introduced into the stack to burn the waste gases of combustion in a secondary combustion zone. To conserve energy, the air being introduced to the incinerator can be preheated by passing the incoming air in heat transfer relation with heated surfaces of the incinerator.
With the use of large industrial-type incinerators, tremendous quantities of heat are generated. In some installations, the incinerator may be located within a building or other enclosed area so that it is desirable to cool the incinerator to prevent the surrounding area from being overheated.
Ash removal is a problem encountered in incineration processes. In large, municipal-type incinerators, movable grates are frequently utilized which will agitate the ash and cause the ash to drop through the grates to a collection area. However, industrial-type incinerators, grates are not utilized and many incinerators of this type require periodic manual removal of the ash, requiring a shutdown of the incinerator during periods of ash removal.
Some industrial incinerators employ an automatic ash removal system, such as that disclosed in U.S. Pat. No. 4,074,638. In the aforementioned patent, a generally cylindrical arm, which is normally located outside of a combustion chamber, is periodically moved across the chamber to agitate the ash and push a quantity of ash into a collection site at the opposite side of the combustion chamber.